/*
 * This is free and unencumbered software released into the public domain.
 * See UNLICENSE.
 */
package scala_maven;

import java.io.File;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import org.apache.maven.project.MavenProject;

/**
 * Grossly hacky utility class which provides the fully unpacked OSGI classpath (ie. including
 * nested .jars) when used in the context of Tycho and Maven 3. The use of reflection is required to
 * avoid wiring in a dependency on either Tycho or Maven 3.
 *
 * @author miles.sabin
 */
class TychoUtilities {
  private static final String TychoConstants_CTX_ECLIPSE_PLUGIN_CLASSPATH =
      "org.eclipse.tycho.core.TychoConstants/eclipsePluginClasspath";
  private static final Method getContextValueMethod;
  private static final Method getLocationsMethod;

  static {
    Method getContextValueMethod0 = null;
    Method getLocationsMethod0 = null;
    try {
      final Class<?> mpClazz = MavenProject.class;
      getContextValueMethod0 =
          AccessController.doPrivileged(
              (PrivilegedExceptionAction<Method>)
                  () -> {
                    Method m = mpClazz.getDeclaredMethod("getContextValue", String.class);
                    m.setAccessible(true);
                    return m;
                  });

      final Class<?> cpeClazz = Class.forName("org.codehaus.tycho.ClasspathEntry");
      getLocationsMethod0 =
          AccessController.doPrivileged(
              (PrivilegedExceptionAction<Method>)
                  () -> {
                    Method m = cpeClazz.getDeclaredMethod("getLocations");
                    m.setAccessible(true);
                    return m;
                  });
    } catch (ClassNotFoundException | PrivilegedActionException ex) {
    }
    getContextValueMethod = getContextValueMethod0;
    getLocationsMethod = getLocationsMethod0;
  }

  @SuppressWarnings("unchecked")
  static List<String> addOsgiClasspathElements(MavenProject project) {
    if (getLocationsMethod == null) {
      return Collections.emptyList();
    }

    List<Object> classpath =
        (List<Object>) getContextValue(project, TychoConstants_CTX_ECLIPSE_PLUGIN_CLASSPATH);
    if (classpath == null || classpath.isEmpty()) return Collections.emptyList();

    List<String> osgiClasspath = new ArrayList<>();
    for (Object classpathEntry : classpath) {
      for (File file : getLocations(classpathEntry)) osgiClasspath.add(file.getAbsolutePath());
    }
    return osgiClasspath;
  }

  private static Object getContextValue(MavenProject project, String key) {
    try {
      return getContextValueMethod.invoke(project, key);
    } catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e) {
      return Collections.emptyList();
    }
  }

  @SuppressWarnings("unchecked")
  private static List<File> getLocations(Object classpathEntry) {
    try {
      return (List<File>) getLocationsMethod.invoke(classpathEntry);
    } catch (IllegalArgumentException | IllegalAccessException | InvocationTargetException e) {
      return Collections.emptyList();
    }
  }
}
